Slotted abrasive wheel

ABSTRACT

A grinding wheel has slots angularly disposed across the peripheral grinding face. A tapered recess is provided at the leading radial edge of each slot so as to provide increased air flow through the slots as the wheel rotates. The radially outward edges of each slot are chamfered to increase the available grinding area.

United States Patent Waller et al. Nov. 4, 1975 SLOTTED ABRASIVE WHEEL2,837,878 6/1958 Johnson 51/206 R Inventors: Gustav Martin Waller,Geneva; 3,579,928 5/1971 Held 5l/356 g 'a g f' Landmark Charles FOREIGNPATENTS OR APPLICATIONS 1,132,479 6/1962 Germany 125/15 [73] AssigneezTunco Manufacturing Inc., Geneva,

Ill. Primary Examiner-Donald G. Kelly [22] F1led: Feb. 10, 1975 [21]Appl. No.: 548,773

[ ABSIRACT [2%] }l.S.CCll 5l/2il6 P; 51/356 A grinding wheel has Slotsangularly disposed across lllt. I the peripheral g g face. A taperedrecess i p [58] Field of Search 51/356 206 206 vided at the leadingradial edge of each slot so as to 51/206'5 125/15 provide increased airflow through the slots as the wheel rotates. The radially outward edgesof each slot [56] References C'ted are chamfered to increase theavailable grinding area.

UNITED STATES PATENTS 8/1936 Sherk 51/206 P 6 Claims, 4 Drawing FiguresUS. Patent Nov. 4, 1975 3,916,579

SLOTTED ABRASIVE WHEEL Grinding wheels have been used to grind away theblack rubber from the outer wall of automotive tires to expose the whiterubber and provide thereby the socalled white wall tire. The grindingoperation, for many years after its inception, was extremely inefficientbecause the rubber which was ground from the tire tended to rapidly clogthe grinding wheel and greatly reduced its efficiency and working life.Such grinding wheels also tended to overheat and this also contributedto short wheel life.

The problem was partially overcome by the addition of angularly disposedslots in the peripheral grinding face of the wheel, thereby providingreservoirs through which the fine residue of ground-up rubber particlescould escape. Such slots also, by flow of air therethrough as the wheelrotated, alleviated the build-up of heat resulting in a more efficientwheel with a longer grinding life. These wheels, however, were still notcompletely satisfactory in that they retained some tendency to clog andthere still was an objectionable bui1dup of heat during a grindingoperation.

It has been found that increased air flow can beattained by theprovision of a tapered recess in the face of the wheel at the leadingedge of each wheel slot. The purpose of the recesses is to relieveslightly the leading edge of each slot so that the trailing edge canscoop up an increased volume of air and direct it down the slot toeffectively clear out the residue of ground rubber.

It is an object therefore, of the present invention to modify the slotstructure of a slotted grinding wheel so as to increase the efficiencyand life of the wheel.

Other objects will be apparent from the following description andaccompanying drawings wherein:

FIG. 1 is a side elevational view of a grinding wheel incorporating thefeatures of the present invention;

FIG. 2 is an end elevational view of the grinding wheel;

FIG. 3 is a fragmentary sectional view taken substantially along line3-3 of FIG. 2; and

FIG. 4 is a fragmentary sectional view taken substantially along line4-4 of FIG. 2.

Referring now to the drawings, a grinding wheel includes opposed faces12 and 13 and a peripheral surface 14. The surface 14 and, if desired,the faces 12 and 13 are provided with an abrasive coating. The wheel mayinclude hubs 16 and a central bore 18 for mounting the grinding wheel ona drive shaft or the like.

Transverse slots 20 are spaced around the peripheral surface 14, theslots being disposed preferably at an angle of approximately 50 relativeto the wheel axis 22. The number of slots will vary with the wheeldiameter and typically a 6 inch diameter wheel may include 6 slots whilea 12 inch diameter wheel will include 18 slots. The width and depth ofthe slots will also vary as desired but preferably may be approximatelyinches wide and /4 inches deep.

The wheel face, at the leading edge of each slot in the direction ofwheel rotation, is provided with a tapered recess 26. The tapered recess26 originates at the wheel face ahead of each corresponding slot in thedirection of wheel rotation and tapers inwardly from the face and towardthe slot. The recess preferably has a depth, radially of the grindingwheel, substantially equal to the depth of the corresponding slot. Thetaper angle of the recess, in a direction away from the grinding wheelface, may vary considerably and still provide the advantage of increasedair flow. However, an angle of approximately l0 has been utilized andfound to be satisfactory.

With the provision of the relief at the leading edge of each slot,sufficient air is picked up to clear the residue of ground rubber out ofthe slots and thereby provide a cooler running grinding wheel and onewhich will have considerably less tendency to clog. The wheel also tendsto run much more quietly than prior art slotted wheels and it isbelieved that this characteristic results from the particular angularityof the slots. The surfaces of the recesses may also, if desired, beprovided with an abrasive coating.

It is advantageous also, to provide'recesses (see FIG. 2) at both facesof the wheel and at diagonally opposite edges of each slot so as toaccommodate wheel rotation in either direction.

Still greater advantages can be obtained by the provision of chamfers 28at the radially outermost edges of the slots at the juncture thereofwith the peripheral face of the wheel. Such chamfers are coated withabrasive material and provide a lead-in surface for the cutting edge andthereby increase the grinding area which is presented to the materialbeing ground. Such chamfers also substantially eliminate the problem ofwearing away the abrasive material from the otherwise sharp corners ofthe slot.

What Is claimed is:

1. A grinding wheel having opposed faces and-a peripheral abrasivecoated grinding surface; a plurality of transverse slots in saidperipheral surface, said slots being angularly disposed relative to thewheel axis and extending across the entire width of the peripheralsurface; the wheel face, at the leading edge of each slot in thedirection of wheel rotation, being recessed at said edge forapproximately the full radial depth of the slot so as to provideincreased air flow through the slots as the wheel rotates.

2. A grinding wheel according to claim 1 wherein each recess originatesat the wheel face ahead of the corresponding slot in the direction ofwheel rotation and tapers inwardly from the face toward the slot.

3. A grinding wheel according to claim 2 wherein the angle of taper ofthe recess is about 10.

4. A grinding wheel according to claim 1 wherein corresponding recessesare provided in both wheel faces, the recesses for each slot being atdiagonally opposite sides thereof to accommodate wheel rotation ineither direction.

5. A grinding wheel according to claim 1 wherein the outer transverseedges of each slot are chamfered and the chamfered surfaces are coatedwith abrasive material.

6. A grinding wheel according to claim I wherein the slots are disposedat an angle of approximately 50 from the wheel axis.

1. A grinding wheel having opposed faces and a peripheral abrasivecoated grinding surface; a plurality of transverse slots in saidperipheral surface, said slots being angularly disposed relative to thewheel axis and extending across the entire width of the peripheralsurface; the wheel face, at the leading edge of each slot in thedirection of wheel rotation, being recessed at said edge forapproximately the full radial depth of the slot so as to provideincreased air flow through the slots as the wheel rotates.
 2. A grindingwheel according to claim 1 wherein each recess originates at the wheelface ahead of the corresponding slot in the direction of wheel rotationand tapers inwardly from the face toward the slot.
 3. A grinding wheelaccording to claim 2 wherein the angle of taper of the recess is about10*.
 4. A grinding wheel according to claim 1 wherein correspondingrecesses are provided in both wheel faces, the recesses for each slotbeing at diagonally opposite sides thereof to accommodate wheel rotationin either direction.
 5. A grinding wheel according to claim 1 whereinthe outer transverse edges of each slot are chamfered and the chamferedsurfaces are coated with abrasive material.
 6. A grinding wheelaccording to claim 1 wherein the slots are disposed at an angle ofapproximately 50* from the wheel axis.